Instead of having to mix your own paint I have found that Autocolor Library has the original Ditzler paint codes for all the 64, 65, 66 trucks. PPG bought Ditzler out and in their OMNI series of regular enamal paint they have the formulas for the original colors. On the Interior paints it is mixed with a lot of reducer in it to flatten the color, i.e if you would normally add reducer 1:1 for Medium Fawn Metalic a exterior color, the interior color medium fawn metalic has so much reducer in it that you only add 1/8th or 1/16th the reducer when you get ready to shoot it .
All of the exterior colors are available in OMNI single stage and also in Base Coat Clear Coat.